1/*-
2 * Copyright (C) 1996
3 *	David L. Nugent.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY DAVID L. NUGENT AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL DAVID L. NUGENT OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#ifndef lint
28static const char rcsid[] =
29  "$FreeBSD$";
30#endif /* not lint */
31
32#include <stdlib.h>
33#include <string.h>
34
35#include "bitmap.h"
36
37struct bitmap
38bm_alloc(int size)
39{
40	struct bitmap   bm;
41	int             szmap = (size / 8) + !!(size % 8);
42
43	bm.size = size;
44	bm.map = malloc(szmap);
45	if (bm.map)
46		memset(bm.map, 0, szmap);
47	return bm;
48}
49
50void
51bm_dealloc(struct bitmap * bm)
52{
53	free(bm->map);
54}
55
56static void
57bm_getmask(int *pos, unsigned char *bmask)
58{
59	*bmask = (unsigned char) (1 << (*pos % 8));
60	*pos /= 8;
61}
62
63void
64bm_setbit(struct bitmap * bm, int pos)
65{
66	unsigned char   bmask;
67
68	bm_getmask(&pos, &bmask);
69	bm->map[pos] |= bmask;
70}
71
72void
73bm_clrbit(struct bitmap * bm, int pos)
74{
75	unsigned char   bmask;
76
77	bm_getmask(&pos, &bmask);
78	bm->map[pos] &= ~bmask;
79}
80
81int
82bm_isset(struct bitmap * bm, int pos)
83{
84	unsigned char   bmask;
85
86	bm_getmask(&pos, &bmask);
87	return !!(bm->map[pos] & bmask);
88}
89
90int
91bm_firstunset(struct bitmap * bm)
92{
93	int             szmap = (bm->size / 8) + !!(bm->size % 8);
94	int             at = 0;
95	int             pos = 0;
96
97	while (pos < szmap) {
98		unsigned char   bmv = bm->map[pos++];
99		unsigned char   bmask = 1;
100
101		while (bmask & 0xff) {
102			if ((bmv & bmask) == 0)
103				return at;
104			bmask <<= 1;
105			++at;
106		}
107	}
108	return at;
109}
110
111int
112bm_lastset(struct bitmap * bm)
113{
114	int             szmap = (bm->size / 8) + !!(bm->size % 8);
115	int             at = 0;
116	int             pos = 0;
117	int             ofs = 0;
118
119	while (pos < szmap) {
120		unsigned char   bmv = bm->map[pos++];
121		unsigned char   bmask = 1;
122
123		while (bmask & 0xff) {
124			if ((bmv & bmask) != 0)
125				ofs = at;
126			bmask <<= 1;
127			++at;
128		}
129	}
130	return ofs;
131}
132